#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <signal.h>
#include <sys/types.h>
#include <unistd.h>

/*#define UNW_LOCAL_ONLY*/
#include <libunwind.h>

#define USE_TIMER

#define panic(args...) \
        do { fprintf (stderr, args); exit (EXIT_FAILURE); } while (0)

static int loop = 1;

#ifdef USE_TIMER
static void sig_handler (int sig, siginfo_t *si, void *uc1)
#else
static void sig_handler (int sig)
#endif
{
  unw_cursor_t cursor;
  unw_context_t uc;
  int ret;

  loop = 0;

  unw_getcontext (&uc);

  if (unw_init_local (&cursor, &uc) < 0)
    panic ("unw_init_local() failed\n");

  do
    {
      unw_word_t ip, sp, offp;
      char buf[512];

      unw_get_reg (&cursor, UNW_REG_IP, &ip);
      unw_get_reg (&cursor, UNW_REG_SP, &sp);
      unw_get_proc_name (&cursor, buf, sizeof (buf), &offp);
      if (unw_is_signal_frame (&cursor))
	printf ("signal frame\tip: %10p, sp: %10p   %s\n", (void*) ip, (void*) sp, buf);
     else
	printf ("standard frame\tip: %10p, sp: %10p   %s\n", (void*) ip, (void*) sp, buf);
    }
  while ((ret = unw_step (&cursor)) > 0);

  if (ret < 0)
    panic ("unw_step() failed\n");
}

#ifdef USE_TIMER
static void setup_timer (void)
{
  struct sigaction act;
  struct sigevent sev;
  timer_t timerid;
  struct itimerspec its;

  memset (&its, 0, sizeof (its));

  /* establish a handler for the timer signal */
  act.sa_flags = SA_SIGINFO;
  act.sa_sigaction = sig_handler;

  if (sigaction (SIGRTMIN, &act, NULL) == -1)
    panic ("sigaction failed\n");

  /* create the timer */
  sev.sigev_notify = SIGEV_SIGNAL;
  sev.sigev_signo = SIGRTMIN;
  sev.sigev_value.sival_ptr = &timerid;
  if (timer_create(CLOCK_REALTIME, &sev, &timerid) == -1)
    panic ("timer_create\n");

  /* start the timer */
  its.it_value.tv_sec = 1; /* 1 second */
  if (timer_settime(timerid, 0, &its, NULL) == -1)
    panic ("timer_settime\n");
}
#endif

int
main ()
{
#ifdef USE_TIMER
  setup_timer ();
  while (loop);
#else  
  signal (SIGUSR1, sig_handler);
  kill (getpid (), SIGUSR1);
#endif
  return 0;
}